S100A9 Antibodies

Structure of S100A9

S100A9 is a calcium-binding protein with a molecular weight of approximately 13.2 kDa. Its precise molecular weight varies slightly among different species due to differences in amino acid sequences.

This protein is composed of 114 amino acids and forms a stable dimer conformation through its primary structure. The core structure of S100A9 contains two EF-hand mods, a characteristic domain that enables it to specifically bind calcium ions. The sparse pockets on the protein surface and the zinc ion binding sites determine its interaction ability with the target protein. Two helical-ring-helical regions are connected through hinge regions. After calcium ions combine, conformational rearrangement occurs, exposing hydrophobic residues and thereby regulating their biological functions.

Fig. 1 Binding model between S100A9 protein and VNN1 protein.¹

Key structural properties of S100A9:

• Stable EF-hand calcium-binding domain configuration
• Conservative polymerization interface to form two hydrophobic core
• Zinc ion binding sites regulate immune function

Functions of S100A9

The core function of S100A9 is to regulate inflammatory responses and immune responses. Meanwhile, it is also involved in various pathophysiological processes such as cell migration, tumor progression and oxidative stress.

The calcium ion binding curve of S100A9 shows a synergistic effect, similar to calmodulin, indicating that it can serve as a key converter for intracellular calcium signals and inflammatory responses.

Applications of S100A9 and S100A9 Antibody in Literature

1. Shen, Shichun, et al. "Single-cell RNA sequencing reveals S100a9hi macrophages promote the transition from acute inflammation to fibrotic remodeling after myocardial ischemia‒reperfusion." Theranostics 14.3 (2024): 1241. https://doi.org/10.7150/thno.91180

This study reveals that S100A9 highly expressing macrophages exacerbate acute inflammation through the Myd88/NFκB/NLRP3 pathway after myocardial ischemia-reperfusion, and promote fibrosis and macrophage-myofibroblast transformation through TGF-β/p-smad3 signaling. Targeted inhibition of S100A9 can effectively alleviate this pathological process.

2. Liu, Xi, et al. "S100A9 deletion in microglia/macrophages ameliorates brain injury through the STAT6/PPARγ pathway in ischemic stroke." CNS Neuroscience & Therapeutics 30.8 (2024): e14881. https://doi.org/10.1111/cns.14881

Studies have confirmed that the high expression of S100A9 macrophages is the key to the deterioration of prognosis after myocardial ischemia-reperfusion. It drives early inflammation and activates TGF-β signaling, directly promoting fibrosis through macrophage-myofibroblast transformation. Targeting S100A9 can effectively alleviate this process.

3. Franz, Sandra, et al. "Overexpression of S100A9 in obesity impairs macrophage differentiation via TLR4-NFkB-signaling worsening inflammation and wound healing." Theranostics 12.4 (2022): 1659. https://doi.org/10.7150/thno.67174

Research has found that overexpression of S100A9 in an obese environment is the key factor leading to dysfunction of macrophages. It forms a vicious cycle with saturated fatty acids, inhibiting the differentiation of anti-inflammatory M2-type macrophages by activating the TLR4/NF-κB pathway, thereby exacerbating skin inflammation and hindering wound repair. Targeted inhibition of S100A9 can effectively break this cycle.

4. Huo, Shengqi, et al. "Macrophage-derived S100A9 promotes diabetic cardiomyopathy by disturbing mitochondrial quality control via STAT3 activation." International Journal of Biological Sciences 21.7 (2025): 3061. https://doi.org/10.7150/ijbs.111128

This study reveals that macrophage-derived S100A9 is a key mediator in diabetic cardiomyopathy. It causes cardiac dysfunction by activating the STAT3 signal in myocardial cells, leading to excessive mitochondrial division and disorder of the quality control system. Targeting S100A9 can effectively improve the above-mentioned pathological processes.

5. Zhang, Yanting, et al. "Deficiency of S100A9 alleviates sepsis-induced acute liver injury through regulating AKT-AMPK-dependent mitochondrial energy metabolism." International Journal of Molecular Sciences 24.3 (2023): 2112. https://doi.org/10.3390/ijms24032112

This study reveals for the first time that S100A9 aggravates liver injury by inhibiting the AMPK pathway and disrupting mitochondrial energy metabolism in acute liver injury caused by sepsis. Intervention with the S100A9 inhibitor Paquinimod can effectively improve liver function and energy metabolism, providing a new idea for clinical prevention and treatment.

Creative Biolabs: S100A9 Antibodies for Research

Creative Biolabs specializes in the production of high-quality S100A9 antibodies for research and industrial applications. Our portfolio includes monoclonal antibodies tailored for ELISA, Flow Cytometry, Western blot, immunohistochemistry, and other diagnostic methodologies.

• Custom S100A9 Antibody Development: Tailor-made solutions to meet specific research requirements.
• Bulk Production: Large-scale antibody manufacturing for industry partners.
• Technical Support: Expert consultation for protocol optimization and troubleshooting.
• Aliquoting Services: Conveniently sized aliquots for long-term storage and consistent experimental outcomes.

For more details on our S100A9 antibodies, custom preparations, or technical support, contact us at email.